Disruption in Quorum-Sensing Systems and Bacterial Biofilm Inhibition by Cembranoid Diterpenes Isolated from the Octocoral Eunicea knighti

摘要

Three new cembranoid diterpenes, knightine (1), 11(R)-hydroxy-12(20)-en-knightal (2), and 11(R)-hydroxy-12(20)-en-knightol acetate (3), were isolated as minor constituents of the Caribbean gorgonian Eunicea knighti, along with the known cembranoids 4–8. The stereostructures of the new compounds were determined by detailed spectroscopic analyses and a combination of chemical transformations and modified Mosher’s methods. All isolated cembranoids were tested against fouling using a quorum-sensing inhibition (QSI) assay and a biofilm inhibition test. Compounds 2, 3, and 6 disrupted QS systems at lower concentrations than kojic acid and Cu2O, and in most cases cembranoids 1–8 showed bacterial biofilm inhibition at lower concentrations than kojic acid.